Purging system for refrigerating plants



1,602,462 T. SHIPLEY PUR-GING SYSTEM FOR REFRIGERATING PLANTS Filed Oct.19b 1925 Il l Q JL ."9

an To SUCT\ON 6 oF c'ompssso HX I. J5 li 18 7 Patented Oct. 12, 1926.

UNITED STATES 'IIHOMASv SHIPLEY, OF YORK, PENNSYLVANIA.

PURGING SYSTEM FOR REFRIGERATING PLANTS.

Application filed October 19, 1925.

This invention relates to refrigeration and particularly to devices forpurging foreign gases from the system.

These foreign gases are ordinarily air and products resulting from thedecomposition of lubricating oils, and h-ave the characteristic of beingnon-condensible at the pressures and temperatures used in refrigeratingsystems. This fact rend-ers their presence harmful to the economicaloperation of the refrigerating system and is availed of for theirremoval by selective liquefaction.

Various methods involving select-ive liquefaction have heretofore beenproposed. The eiiicacy of such methods depends on the thoroughness withwhich the mixture of gases is chilled. It is impossible, according tothe law of partial pressures, to produce a complete separation in thisway, but a .separation complete enough for practical purposes can be hadif the mixture of gases is cooled to a sufliciently low temperature andif all parts Iof the mixture are maintained chilled at the point ofpurging. be done satisfactorily in a device arranged to be manuallyoperated and hence operated only periodically, but it has been found'difficult to secure satisfactory results with a device capable ofoperating automatically and substantially continuously. Continuousautomatic operation is obviously desirable.

Generally stated, I withdraw from the system refrigerant in a gaseousstate with a rich admixture of foreign gases. This can best be done atpoints in the system where the refrigerant is normally in a liquidstate, for gases and vapors there present will be richest in foreigngases. A convenient way to collect such gas mixture is to interpose at-rap in the liquid line as shown in my prior Patents Nos. 1,525,006 and1,525,007, issued February 3, 1925, or to take advantage of the trappingaction inherentlyV present in the conventional type of receiver. Thislast arrangement is shown in the present application.

The mixture of gases so accumulated is led through one passage 4of asurface cooler which has another passage through which a cooling mediumis passed in counter-How relation. This cooling medium may convenientlybe refrigerant from the system expanded through an expansion valve andreturned to the suction side of the compressor, or its equivalent. is toliquefy substantially all of the refrig- This can The effect of thecooler'l serial No. 63,490.

erant gas so that the discharge from the cooler consists of liquidrefrigerant and noncondensible gases with a very slight admixture ofrefrigerant in the gaseous state. The

discharge from the cooler is received in a Idrum which preferablyencloses the entire cooler and in which a gravity separation of theliquid and gas is effected.

The liquid refrigerant is discharged by automatic means, preferably afloat valve,

through a valve, preferably automatic, the

simplest form of which is an ordinary loadedv relief valve. This reliefvalve is set open at a pressure slightly less than receiver pressure inthe system so as to induce flow of gases through the cooler.

In order to observe the operation of the device a sight glass isinterposed between the refrigerating system and the cooler. This sightglass contains liquid, preferably oil, through which the gases bubblewhen the system is operating correctly.-

Instead of the loaded relief valve above referred to, I may make use ofany other suitable type of valve for controlling the purging. A manuallyoperated yalve might be used with some success, and there are othertypes of automatically controlled valve which may be applied and whoseuse under particular circumstances is contemplated.

The system is illustrated partly in elevation and partly in section inthe accompanying drawing.

The receiver is shown at 1. The connection 2 leads from the top of thereceiver through a stop valve 3 to the bottom of a sight glass 4. Thisis substantially filled with a liquid such as oil, through which the gasbubbles upward. From the top of the sight glass 4 connection is made toa two-pipe cooler consisting of an internal pipe 5 and a surroundingcooling pipe 6. These pipes are concentrically arranged and the innerpipe 5, which receives the gases from the sight glass 4, discharges atits lower end 7 into a drum 8 known as the purge drum. i

The drum S makes a tight joint with the outer pipe 6. On the upper endof the outer pipe 6 is a T coupling9 to which is connected a pipe 10leading to the suction side of the compressor or its equivalent formingpart of the refrigerating system. A tight joint between the coupling 9and the pipe 5 is iliade by means of a thimble 11. The pipe 12 bringsliquid refrigerant from some suitableV source, such as the receiver 1,and delivers it through an expansion valve 13 to a pipe 1-1 whichextends through the top of the purge drum 8 and connects at 15 with thespace between the outer pipe G and the inner pipe 5. The pipe 1-1 makesa tight joint with the purge drum S and also with the outer pipe G at15.

Consequently, liquid refrigerant is expanded through the valve 13,passes through the pipe 11i to the annular space between the pipes 5 and6 ofthe cooler,.thence flows upward through this space, and flows to thecompressor through the connection 10. rIhe effect of this is to chillthe gases flowing downward through the pipe 5 and also to chill theinterior of the drum 8. j

It will be observed that the counter-flow principle is availed of in thepipes 5 and G so that gases flowing from the receiver 1 are thoroughlychilled, and this chilling action is maintained within the drinn 8.Consequently, substantially all the refrigerant flowing down through thepipe 5 is discharged as a liquid at 7 and collects in the bottom of thedrinn 8. rlhe level of liquid there indicated by a gauge glass 16 ofusual form. The liquid is discharged from time to time through a valve17 which may be automatically controlled by means of a float 18, thougha manually operated valve might be substituted if preferred.

From the valve 17 the refrigerant flows through a pipe 19 to the pipe14. I-Ience the valve 17 acts as a sort of expansion valve, admittingliquid refrigerant to the space between the pipes 5 and G of the cooler.Since this space is connected with the suction of the compressor, thisforms a convenient and eflicient way of returning the liquid refrigerantfrom the bottom of the drum 8 to the refrigerating system. j

rI`he pipe 2() leads from the top of the drum 8 and to this is connecteda pressure gauge 21 and a loaded relief valve 22 which is set to apressure slightly less than the pressure in the receiver 1. Accordingly,the relief valve 22 operates to vent from the purge drum 8 the foreigngases which gradually accumulate there. Instead of the pressurecontrolled relief valve-22 I may substitute other automatic valves,particularly valves subject to the conditions in the drum S. It will beobserved that the valve 22 is subject to pressure conditions in the drumand it is desirable that the purge valve be controlled by suchconditions, though it is not strictly necessary that this control be bypressure.

Also it is not necessary to adhere strictly to the exact arrangementshown, but a peculiar advantage is had from the use of a counter-:flowsurface cooler so arranged as to cool not only the flowing gas, but alsothe interior of the purge drum. Hence I regard the enclosing of thesurface cooler within the purge drum as an in'iportant feature of theinvention.

that is claimed isz- 1. In a purge device for re'lfrigerating systems,the combination of a cooler of the surface type having two passages inheat transferring relation; connections for passing a cooling mediumthrough one passage in said cooler; connections for passing a mixture ofcondensible refrigerant and non-condensible gas from a refrigeratingsystem through the second passage in said cooler in counterflow relationto said cooling medium; a chamber for collecting liquid refrigerantcondensed in said second passage; and an automatic vent valve subject toconditions in the chamber arranged to discharge uncondensed gases fromsaid chamber.

2. In a purge device for refrigerating systems, the combination of acooler of the surface type having two passages in heat transferringrelation; connections for passinga cooling medium through one passage insaid cooler; connections for passing a mixture of condensiblerefrigerant and noncondensible gas from a refrigcrating system throughthe second passage in said cooler in counter-flow relation to saidcooling medium; a` chamber for collecting liquid refrigerant condensedin said second passage; and a loaded relief valve for discharginguncondensed gases from said chamber.

3. In a purge device for refrigerating systems, the combination of adouble pipe cooler; connections for passing a cooling medium through onepipe of said cooler; connections for passing a mixture of condensiblegaseous refrigerant and non-condensible gas from a refrigerating systemthrough the second pipe of sai-d cooler; a drum enclosing said coolerand arranged to receive the discharge from said second pipe; aiijomati vvalve means forwithdrawing liquid refrigerant from said drum; and anautomatic vent valve arranged to discharge uncondensed gas from saiddrum.

4. In apurge device for refrigerating systems, the combination of adouble pipe cooler; connections for expanding refrigerant from arefrigerating system through one pipe of said cooler; connections forpassing mixture of condensible gaseous refrigerant and non-condensiblegas from the refrigerating system through the second pipe of sai-dcooler; a drum enclosing said cooler and arranged to receive thedischarge from said second pipe; automatic means arranged toV Withdrawliquid refrigerant from said druin and deliver it to the first pipe ofsaid cooler; and an automatic Vent valve arranged to dischargeuncondensed gas from said dru'ni.

5. In a purge device for refrigei'ating systeins, the combination of acooler comprising concentric pipes arranged in a substantially verticalcoil; Connections for expanding refrigerant from a refrigeratiiig systemupward 'through the space between said inner and outer pipes;connections for passing a mixture of condensible gaseous refrigerant andnon-condensible gas downward through inner and' outer pipes; and anautoinatic- Vent valve subject to conditions within said druni andarranged' to. discharge uncondensed gases froni said druin.

In testimony whereof I have signed naine to this specification.

THOMAS si-iriDLnY.-

